PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Pregnant women with hepatitis C may pass heartier viral strain to newborns, study suggests

2013-10-28
(Press-News.org) Contact information: Mary Ellen Peacock
maryellen.peacock@nationwidechildrens.org
614-355-0495
Nationwide Children's Hospital
Pregnant women with hepatitis C may pass heartier viral strain to newborns, study suggests Infants who get hepatitis C from their mothers during childbirth may inherit a viral strain that replicates more quickly than strains found in non-pregnant hosts, according to a new study published Oct. 27 in Nature Medicine. The findings, from a team in The Research Institute at Nationwide Children's Hospital, are the first to describe how a virus that has infected 180 million people worldwide takes advantage of immune changes during pregnancy.

About 1 percent of all pregnant women worldwide have hepatitis C, caused by a highly adaptable virus known as HCV that infects liver cells. In 3 to 5 percent of these pregnancies, the virus is passed to the newborns, accounting for the majority of new childhood HCV infections. Between 15 and 45 percent of people infected with HCV are able to mount an immune response sufficient to eradicate the virus. But in most cases, the virus eludes immunity, leading to a chronic infection that increases the risk of liver failure or liver cancer.

As part of a larger study of HCV in pregnant women and infants, researchers at Nationwide Children's followed two women with hepatitis C over a five-year period. Both women had two children during this time, and researchers were able to track the virus before, during and after pregnancy. Their analysis revealed surprising changes in HCV genomes that not only allowed the virus to thrive, but also ensured that the strain passed on by one of the women during childbirth was particularly good at replication, says Jonathan R. Honegger, MD, an infectious disease specialist and principal investigator in the Center for Vaccines and Immunity at Nationwide Children's.

"We found that better replicating versions of the virus emerged during pregnancy, and these 'fit' viruses were passed to the babies." Dr. Honegger says. "The findings actually provide unique insight into the impact of pregnancy on the mothers' control of viral infections, and also a striking illustration of this virus' ability to adapt to changing environmental pressures."

HCV persists in the general population, in part, because the virus outwits the immune system with mutations that can render it undetectable to CD8+ T-cells, important weapons in the body's antiviral immune arsenal. Although these viral variations—called immune escape mutations—protect the virus from attack by T-cells, they sometimes slow the virus replication machinery.

During pregnancy, T-cells are restrained to prevent the body from attacking the fetus as foreign tissue. Viral levels of HCV have also been known to increase during pregnancy, but whether this was related to changes in T-cell function was unknown. Working closely with Chris Walker, director of the Center for Vaccines and Immunity, and colleagues at Emory University and the University of North Carolina, Dr. Honegger found that during pregnancy, certain T-cell escape mutations were lost, resulting in a virus that could replicate far more quickly.

"This surprised us because the virus' immune escape mutations are usually stable in a patient," Dr. Honegger says. "The loss of these immune escape mutations from HCV during pregnancy provided strong evidence that the immune changes of pregnancy, intended to protect the fetus, significantly impaired the ability of CD8+ T-cells to exert pressure on the virus."

Loss of the escape mutations also meant that the babies got a version of the virus that was optimized for viral replication, Dr. Honegger adds. In the children they studied, the virus persisted and did not mutate in a way to suggest that it was under significant attack by their CD8+ T-cells.

"We don't yet know whether getting the fast-replicating, immune-susceptible version of the virus would be an advantage for the baby or the virus," says Dr. Honegger, who also is an assistant professor of pediatrics at The Ohio State University. "We suspect that if the baby doesn't mount a swift and strong immune response, then fast viral replication may increase the risk of persistent infection in the baby."

On the other hand, viral loads in the mothers dropped more than 1,000 fold by 12 weeks after delivery and viral genetic analysis showed that immune escape mutations had returned. "We interpreted this to mean that T-cell activity against hepatitis C in the liver increased sharply after delivery," Dr. Honegger says.

Researchers now are following a larger group of pregnant women with HCV, hoping to learn more about how viral mutations affect the way the body controls hepatitis C in pregnant women and infants.

"We believe that better understanding of the natural history of the infection in these patients will be critical for designing rational strategies to treat or prevent HCV in these populations."

INFORMATION:

Full citation: Honegger JR, Kim S, Price AA, Kohout JA, McKnight KL, Prasad MR, Lemon SM, Grakoui A, Walker CM. Loss of Immune Escape Mutations During Persistent HCV Infection in Pregnancy Enhances Replication of Vertically Transmitted Viruses. Nature Medicine. 2013 Oct 27. doi: 10.1038/nm.3351 [Epub ahead of print]

Funding: This work was supported by the US National Institutes of Health (R37-AI47367 to C.W, R56-AI096882 and R01-AI096882 to C.W and J.H., RO1-DA024565 and R01-AI95690 to S.L., R01-AI070101 and R01-DK083356 to A.G., T32-HD043003 and K12-HD043372 to J.H., and the Yerkes Research Center Base Grant P51RR-000165 (A.G.)), The Research Institute at Nationwide Children's Hospital (C.W. and J.H.), and the University of North Carolina University Cancer Research Fund (S.L.).

END



ELSE PRESS RELEASES FROM THIS DATE:

Researchers measure flow from a nanoscale fluid jet

2013-10-28
Researchers measure flow from a nanoscale fluid jet Jet measures 20 to 150 nanometers in diameter -- just a few hundred water molecules across Fluid jets are all around us: from inkjet printing, to the "Old Faithful" geyser in Yellowstone National Park, to ...

Historic demonstration proves laser communication possible

2013-10-28
Historic demonstration proves laser communication possible In the early morning hours of Oct. 18, NASA's Lunar Laser Communication Demonstration (LLCD) made history, transmitting data from lunar orbit to Earth at a rate of 622 Megabits-per-second ...

What do we know -- and not know -- about fracking?

2013-10-28
What do we know -- and not know -- about fracking? 2013 GSA Annual Meeting Pardee Keynote Sympsium Boulder, Colo., USA - Fracking is in the headlines a lot these days, and everyone has an opinion about it. But how much do we really know for certain about the oil and ...

Novel mutations define 2 types of bone tumor

2013-10-28
Novel mutations define 2 types of bone tumor 2 related genes underlie the development of two rare bone tumours in nearly 100 percent of patients Scientists have made a rare discovery that allows them to attribute two types of tumour almost entirely ...

Rare childhood disease may hold clues to treating Alzheimer's and Parkinson's

2013-10-28
Rare childhood disease may hold clues to treating Alzheimer's and Parkinson's Rutgers scientists investigate excess protein production in brain cells Scientists at Rutgers University studying the cause of a rare childhood disease that leaves children unable to ...

Scientists eye longer-term forecasts of US heat waves

2013-10-28
Scientists eye longer-term forecasts of US heat waves BOULDER -- Scientists have fingerprinted a distinctive atmospheric wave pattern high above the Northern Hemisphere that can foreshadow the emergence ...

Radioactive waste: Where to put it?

2013-10-28
Radioactive waste: Where to put it? 2013 GSA Annual Meeting Boulder, CO, USA — As the U.S. makes new plans for disposing of spent nuclear fuel and other high-level radioactive waste deep underground, geologists are key to identifying safe burial sites and techniques. ...

Mount Sinai researchers identify mechanisms and potential biomarkers of tumor cell dormancy

2013-10-28
Mount Sinai researchers identify mechanisms and potential biomarkers of tumor cell dormancy May be able to recreate conditions that keep cancer cells from growing after they have spread Oncologists have long puzzled over ...

Cell nucleus protein in brown fat cells governs daily control of body temperature

2013-10-28
Cell nucleus protein in brown fat cells governs daily control of body temperature Biorhythm of brown fat has implications for combating obesity, associated diabetes and heart disease, finds an interdisciplinary team from Penn Medicine PHILADELPHIA ...

International group finds 11 new Alzheimer's genes to target for drug discovery

2013-10-28
International group finds 11 new Alzheimer's genes to target for drug discovery Global collaboration including Penn Medicine experts yields fresh look at role of immune system in Alzheimer's PHILADELPHIA - The largest international Alzheimer's ...

LAST 30 PRESS RELEASES:

Engineers uncover why tiny particles form clusters in turbulent air

GLP-1RA drugs dramatically reduce death and cardiovascular risk in psoriasis patients

Psoriasis linked to increased risk of vision-threatening eye disease, study finds

Reprogramming obesity: New drug from Italian biotech aims to treat the underlying causes of obesity

Type 2 diabetes may accelerate development of multiple chronic diseases, particularly in the early stages, UK Biobank study suggests

Resistance training may improve nerve health, slow aging process, study shows

Common and inexpensive medicine halves the risk of recurrence in patients with colorectal cancer

SwRI-built instruments to monitor, provide advanced warning of space weather events

Breakthrough advances sodium-based battery design

New targeted radiation therapy shows near-complete response in rare sarcoma patients

Does physical frailty contribute to dementia?

Soccer headers and brain health: Study finds changes within folds of the brain

Decoding plants’ language of light

UNC Greensboro study finds ticks carrying Lyme disease moving into western NC

New implant restores blood pressure balance after spinal cord injury

New York City's medical specialist advantage may be an illusion, new NYU Tandon research shows

Could a local anesthetic that doesn’t impair motor function be within reach?

1 in 8 Italian cetacean strandings show evidence of fishery interactions, with bottlenose and striped dolphins most commonly affected, according to analysis across four decades of data and more than 5

In the wild, chimpanzees likely ingest the equivalent of several alcoholic drinks every day

Warming of 2°C intensifies Arctic carbon sink but weakens Alpine sink, study finds

Bronze and Iron Age cultures in the Middle East were committed to wine production

Indian adolescents are mostly starting their periods at an earlier age than 25 years ago

Temporary medical centers in Gaza known as "Medical Points" (MPs) treat an average of 117 people daily with only about 7 staff per MP

Rates of alcohol-induced deaths among the general population nearly doubled from 1999 to 2024

PLOS One study: In adolescent lab animals exposed to cocaine, High-Intensity Interval Training boosts aversion to the drug

Scientists identify four ways our bodies respond to COVID-19 vaccines

Stronger together: A new fusion protein boosts cancer immunotherapy

Hidden brain waves as triggers for post-seizure wandering

Music training can help the brain focus

Researcher develop the first hydride ion prototype battery

[Press-News.org] Pregnant women with hepatitis C may pass heartier viral strain to newborns, study suggests